What is the correct central ray (CR) placement for a lateral coccyx radiograph?

In radiography, precise central ray placement is crucial for obtaining accurate images of anatomical structures. For a lateral coccyx radiograph, the correct central ray placement is 3.5 inches posterior to the anterior superior iliac spine (ASIS) and 2 inches inferior. This positioning allows for a clear view of the coccyx, ensuring it is centered in the image and minimizing surrounding anatomical structures that could obscure the view.

The location of 3.5 inches posterior to the ASIS helps ensure the CR is appropriately positioned beyond the pelvic region. Going 2 inches inferior targets the area of the coccyx effectively, accounting for the coccyx's anatomical position relative to the ASIS and ensuring that the entire structure is captured in the image.

This level of detail is necessary in diagnostic imaging, particularly for regions with complex anatomy like the pelvis, where misalignment can lead to diagnostic errors. Proper CR placement is essential for accurate diagnosis and treatment planning.